1Carefully clean the chicken liver by removing any visible green bile ducts, sinews, and excess fat. Rinse gently under cold water and pat dry thoroughly with paper towels.
3Prepare the tare sauce: In a small saucepan, combine koikuchi soy sauce, mirin, sake, and granulated sugar. Bring the mixture to a gentle simmer over medium heat, stirring until the granulated sugar is fully dissolved. Reduce the heat to low and let it simmer for 5-7 minutes, allowing the sauce to thicken slightly. Set aside.